MISSOURI'S TERROIR: MAPPING THE PHYSICAL GEOGRAPHY OF THE AUGUSTA AMERICAN VITICULTURAL AREA (AVA)

Physical parameters such as climate, geology, soils, slope, drainage, and aspect can influence the character of wines. Terroir is a French term that loosely refers to a ‘sense of place' that includes these parameters as well as vinicultural practices. The US Department of the Treasury–Alcohol and Tobacco Tax and Trade Bureau (TTB) has designated American Viticultural Areas (AVAs) as discrete entities in the United States that have well-established and historic viticultural practices, but the relationship between terroir and AVAs is complex. Over the last decade, geospatial analysis techniques have been used to evaluate the physical geography of AVAs in California, Washington and Oregon and develop models for vineyard management. Although the winemaking industry of Missouri has a long history, with 74 wineries and four AVAs, rigorous geospatial analyses have not been applied.

In this study, we evaluate the physical geography of Augusta, the first AVA designated in the United States. USDA National Agriculture Imagery Program (NAIP) aerial photographs and soil maps, USGS digital elevation models, and Missouri Division of Geology and Land Survey surficial sediment and geologic maps were used to develop a geodatabase for use in ESRI ArcMap. Only four wineries are located in the Augusta AVA; 53 tracts comprising 138 acres (55.85 ha) are under vine. The largest tract is 8.7 acres (3.52 ha), and the smallest is approximately 0.2 acres (0.08 ha). Elevation ranges from 450 feet (137 m) to 880 feet (268 m). Values for slope range from 2° to 11°; the average slope is 6.5°. The bedrock geology is lower and middle Ordovican mixed carbonates, sandstone, and shale. Loess and sandstone colluvium are primary sources for the overlying Menfro silt loam soils. The geospatial database developed in this study serves as a model for our continuing studies of other AVAs in Missouri. It is anticipated that this information will be useful for oenologists, consumers, and the tourism industry.